Do sports drinks improve running performance?

The rise of the sports drink industry has been astonishing and shows little sign of slowing. Every race I attend seems to have a new drink manufacturer in attendance, keen to tell me why I should drink their product over another competitor – they no longer seem to bother telling me why I should drink a sports drink instead of water, that’s surely common knowledge by now. The industry is worth around £260m in the UK alone and has been the fastest growing soft drinks sector for years. The US market is set to hit a staggering $2bn by 2016.

There seems to be two messages freely given out by the industry and I believe that these have both been embedded in the mind of most runners who accept them as truth:

1) We can’t rely on our thirst to tell us when to drink.
2) Sports drinks are better for our performance than water.

The Gatorade Sports Science Institute have declared: “The human thirst mechanism is an inaccurate short-term indicator of fluid needs…there is no clear physiological signal that dehydration is occurring,” On their website, Poweraid make a similar statement: “Without realising, you may not be drinking enough to restore your fluid balance after working out.”

Sports drinks contain sodium which, we are told, helps to stimulate our thirst – thus tricking the body into retaining more liquid then it otherwise would. This is good because our body doesn’t know it is about to exercise hard and therefore it needs more fluid than it thinks. This is a claim upheld by the European Food Safety Authority (EFSA).

So far, so good for the sports drinks. However, the British Medical Journal (BMJ) has been seen to take a stand against the industry, stating that the studies on which the EFSA based their knowledge were fundamentally floored. They were funded by the sports drinks industry and the studies were based on findings for elite athletes and not the average runner. The BMJ reviewed 431 scientific claims made by sports drinks companies and amazingly, found that only 3, less than 1%, of them were based on studies that were of a ‘good’ standard. For me, this is startling.

Having looked into the dangers of dehydration before running my first marathon, I began to come across more serious stories getting a lot less press which seemed to tell me that actually the real danger is drinking too much liquid. Cynthia Lucero ran the Boston Marathon in 2002, tragically she collapsed after around 22 miles and died of hyponaemia – excess fluid consumption. Hew et al. (2003) reported 21 cases of hyponatremia at the 2000 Houston Marathon, although thankfully none were fatal. I have still not been able to find a confirmed marathon runner death from dehydration. It appears that dehydration as a real problem to runners has been used as a scaremonger tactic by the sports drinks manufacturers, this is a common occurrence in healthcare – if you can produce a product with which to cure a fake illness, you first have to convince people that they are ill.

It took me a long time to realise that the intense headaches that I suffered from after long runs were actually due to my over-drinking fluids. This is a very worrying sign. If you suffer from headaches after a run, it may be that you need to look at your fluid intake before, during and after the exercise and potentially cut it back to only drink when you feel thirsty.

The early 1990’s saw the sports drinks manufacturers move into selling science in a big way. There were large donations to universities and sponsoring of scientific events and forums. Their aim, at least in part, was to introduce sports drinks as the fluid of choice for exercise, replacing water. To make this possible, they needed people to think that sports drinks would improve performance when compared with water alone.

What made me question this for the first time, was when Lucozade told parkrun that “water alone isn’t enough to maintain hydration“. Now, parkrun is a 5km run which is undertaken by (on the whole) ‘normal’ people, surely water along is enough to maintain hydration over such a short race, it’s all I drink at parkrun and I’ve never had a problem, I’m sure that water is enough to maintain hydration and I also don’t believe that dehydration is the problem that Lucozade are making it out to be.

I looked into this in a little more detail and came across this article. It points out a number of issues with the research performed on sports drinks over the last forty years, some of which is startling – including manipulation of the nutrition of subjects in order to distort results of trials, a lack of ‘blind’ trials, so the people performing the research could have, inadvertently or not, influenced the results. The more I read, the more I believe that I’m better off drinking water and eating good quality carbohydrate before and after exercise.

At the end of the day, it’s still up to you, if you believe that the drink is giving you an edge then maybe it will, but I think it’s important to understand that the science may not backup the claims of sports drinks manufacturers at all times – even if there is a study to point to which appears to do so.